Elevator-control system



Oct. 28, 1924. 1,513,243

R. P. HIGBEE ELEVATOR CONTROL SYSTEM Filed Jan. 25 1922 INVENTOR WITNESSES:

Patented Oct. 28, 1924.

UNITED STATES PATENT OFFICE.

RAY I. HIGBEE,'OF WILKINSBUBG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA,

ELEVATOBCONTROL SYSTEM.

Application file-'1 January 25, 1922. Serial No. 531,674.

T 0 all whom concern:

Be it known that I, RAY P. Hieenn, a citizen of the United States, and a resident of .Vilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Elevator- Control Systems, of which the following is a specification.

My invention relates to motor-control systems and it has particular relation to such systems of control as are employed in connection with elevators, hoists and similar machines.

One object of my invention is to provide means whereby an elevator car or a similar body may be actuated at high or low speed by means of a main and an auxiliary machine which be operated simultaneously or independently.

Another object of my invention is to provide, in an elevator system, an arrangement of hoisting cables wherein the car is suspended trom the cables intermediate a main and an auxiliary hoisting machine, either or both of which may beoperated to control the car.

Another object of my invention is to pro vide an electrical system of control for an elevator, having a mechanical arrangement, as set forth, wherein the car is normally under control of an operator and wherein the control becomes automatically independent of the operator when the operators con trolling switch occupies its inoperative or oil position.

Other objects of my invention will appear in the following specification and the appended claims:

The method of suspending the car from the hoisting cables by means of an idler sheave that is attached to the cross-head of the car constitutes what is commonly known as a two-to-one rope hitch. However, such systems commonly provide for the permanent fastening of one end of each cable to a beam at the top of the elevator hatchway. The other ends of the cables usually traverse a hoisting drum or sheave that is attached to the hoisting machine. This machine is commonly either of the geared or the gearless type that is employed in electric elevator systems. Various systems of electrical control have been employed; however, any system of control applicable to an elevator may be utilized, depending, in the main, only upon the car speed.

It is to be noted that the car speed, in the case noted, is one-half the speed of the hoisting cables and that the weight of the car and its superimposed load is equally divided between the overhead points of suspension of the hoisting cables. It is com mon practice to employ such a system where unusually heavy loads are to be handled, as in department stores. The elevators, under such conditions, are rather diflicult to accurately control, on account of the extreme variations in loading conditions, which require the operator to exercise extreme care in order to effect accurate landings, often necessitating inching, with a resultant loss of time.

I propose to employ an elevator system of the two-to-one type, as described, and, in addition, I provide an auxiliary machine to which the hoisting cables are fastened in such manner as to replace the usual stationary hitch. In normal operation, the auxiliary machine remains at rest and provides a stationary hitch for one end of each of the hoisting cables. The main machine is then controlled in the usual manner. When the operator releases the controlling switch, or car switch, as it is commonly termed, to effect a stop at any desired floor, the auxiliary machine becomes effective to operate the car substantially to a level with the desired floor, in case the car tends to undertravel or overtravel by reason of the inherent ineffectiveness of the main operating mechanism.

lVhen normal operation is resumed, the auxiliary machine is automatically restored to its normal position and is, therefore, maintained in readiness to effect an accurate stop when the car is brought to the next desired landing. I prefer to employ a pair oi switches that are mounted on the car and controlled by a cam adjacent to each floor for controlling the auxiliary machine, Within certain li'mitslof travel above and below each floor level.

[The reversing switch 26 is efl'ective only The single figure of the drawing is a diagrammatic' representation of circuits and apparatus embodying my invention.

The main hoisting motor, having an armature 1 and a field-magnet winding 2, is operatively' connected, through reversing switches 3 and 4, to line conductors 5 and 6. The motor is provided with a starting resistor 7 that may be controlled any'wellknown manner, "as'by means of a counter-' sheave 14.- The car is normally controlled by means of a car switch 15;

' 7 An auxiliary .motor, having an armature 16 and a field-magnet winding 17,'is operatively connected, through reversing switches '18 and -19,'to line conductors o and 6. An accelerating resistor 21 is provided for the auxiliary ,motor and is controlled by means of a 'counter-electromotive-force switch '22. Any, other suitable controlling nieansjhowever, maybe employed. 'The, armature 161s preferably connected, through gearing 23, to a hoisting drum 24.

It will be noted that the hoisting cables.

13 are operatively connected, at their opposite ends, respectively, to drums 9 and 24, in a familiar manner. Theaiiziiliary hoisting machine is provided with an electromagnetic brake 25. An auxiliary reversing switch 26 is mounted on the car to be actuated by cams 27 that are located adjacent to the flcoi's'28, for operating the auxiliary control system.

when the car. switch 15 occupies its inoperative position and when thecar is within the described limits, adjacent to the desired landing. A. switch member29, illustrated in its normal position, provides means for re;

,lustrated position bv means of a spring 37,.

storing the auxiliary hoisting machine to its normal position while the main hoisting machine is in operation; .i

The operation of my system will be more clearly understood from the following dc V tailed description. Assuming-that the various switches and apparatus occupy their inoperative positions, as illustrated in the figure, with the hoisting drum 24 station ary, the car 12is hoisted or lowered in the usual manner whenthe cables 13 are wound upon or unwound from thedrum 9. I will designate this operation as reeling the ca-' bles. V-grooved or other type of sheaves may be employed in place of the drums-9 and 24, as will be understood. The main hoisting motor is controlled, ina well-known manner, by means of a car switch 15, the reversing switches 3 and 4 being responsive, respectively, to the actuation of the car switch for upward or downward motion of the car.

The electromagnetic brake 11 is controlled. simultaneously with the operation of either of the reversing switches 3 and 4. and the shunt field-magnet winding 2, as illustrated, V

is normally energized. The acceleration of the motor armature 11s controlled by means of the starting resistor 7 and the counterelectromotiveforce switch 8. Somuch of the operation of my system will be well understood by anyone familiar with motorcontrol systems and should not require par ticular elaboration.

Wlien the operator desires to stop at any floor, the carswitcli is returned to its inoperative'or, illustrated position. In case the car 12 tends to stop below the level of the floor- 28, switch member 31is actuated by the cam 27 to engage stationary contact member A circuit is thereby established for the up direction-switch 18-extending from line conductor 5 through operating coil of the brake 25, operating-coil of switch'18, conductor 33,

conductor 36 to line conductor 6, Switch 18 thereupon closes and brake 25 is released to cause upward movement of the'car 12.

Accelerat on of the armature 16 15.0011- trolled by means of resistor 21 .and accelerating switch 22, in a wellknown manner. The

speedof rotation of the drum 24 is, of course, governed in accordance with the speed of the aanature 16 and'the ratio of gear-wheels 23. The speed ofrotation of-the drum 24 preferably provides for avery low car speed, 7

say 25'feet per minute.

Assuming that the mainhoisting 'drum f) V has came to a position ofirest, the hoist ng when switch 31 isdisengaged from cam 27. The switch contact member 29is actuated-by the auxiliary drum 24 to slidably engage stationary contact member 38. Therefore, when the car switch 15 isneXt actuatedtoan opei' ative position, for either direction of motion of the elevator car, a circuit is established for the reverse motion, to restore drum 24 to its normal or illustrated position.

'A circuit is established for theoperating coil of reversing switch 19 extending from line conductor 5 through operating coil of brake 25, operating coil of switch 19, 0011- ductor 89, contact members 38 and 29 of the auxiliary drum 24, conductor 41, contact 'members 42 and 35 of the car switch 15 and conductor '36 to line conductor 6. During the operation of the car to the next stopping point the drum 24 is rotated to its normal or illustrated position, as described above.

In case the car tends to stop above the desired floor 28, switch member 43 is actuated by the cam 27 to engage stationary contact member 32 and to establish a circuit for th operating coil of reversing switch 19 extend ing from line conductor 5 through operating coil of brake 25, operating coil of switch 19, contact members 43, 32, 34 and 35 and con ductor 36 to line conductor 6. When the car 12 is substantially level with the floor 28, the switch member 43 is restored to its normal position by means of the spring 37. During the downward movement of the car 12, when eli'ected by means of the auxiliary drum 24, the contact member 29 slidably engages contact member 44. Upon actuation of the car switch 15 to either of its operative positions, the drum 24 is restored to its normal position by the closure of reversing switch 18 and the energization of the auxiliary motor for oper ation in a direction reverse to the movement during the previous operation.

A circuit for energizing the coil of switch 18 extends from line conductor 5 through operating coil of brake 25, operating coil of switch 18, conductor 45, contact members 44 and 29, conductor 41, contact members 42 and 35 and conductor 36 to line conductor 6. The armature 16 is thereby automatically controlled to restore the switch member 29 to its normal position.

Any well known type of geared limitswitch may be employed in lieu of the abovementioned apparatus for restoring the drum and contact member 29 to its normal position in the manner described.

I have described a system employing, in addition to standard equipment, an auxiliary machine of similar design to the main hoisting machine, but adapted for slowspeed operation. My system will be found otparticulai' advantage in connection with elevators or hoists of unusually large capacity in which extreme accuracy of stopping is desired, and provides means whereby the platform may be maintained level with any floor during the process of loading or unloading the elevator car.

I claim as my invention:

1. In an elevator system, the combination with a main machine and an auxiliary machine, ot a hoisting cable operatively con nected at one end to the main machine and at the other end to the auxiliary machine, a car suspended from said cable intermediate said machines, and controlling means for said machines comprising a car switch and a switch actuated by said auxiliary machine.

2. In an elevator system, the combination with a main machine and an auxiliary machine, of a hoisting cable operatively con-v nected at one end to themain machine and at the other end to the auxiliary machine, an idler sheave, a car suspended from the cable b means of said idler sheave intermediate said machines, and automatic means for operating said machines independently and simultaneously.

In an elevator system, the combination with a main machine and an auxiliary machine, of a hoisting cable operatively connected at one end to the main machine and at the other end to the auxiliary machine, an idler sheave, a car suspended from the cable by means of said idler sheave, intermediate the said machines, and automatic means for operating said machines simultaneously under predetermined conditions.

4. In an elevator system, the combination with a main machine and an auxiliary machine, ot a hoisting cable operatively con nected at one end to the main machine and at the other end to the auxiliary machine, an idler sheave, a car suspended from the cable by means or" said idler sheave, intermediate the said machines, means for operating said auxiliary machine after said main machine has become ineffective, and means controlled by said auxiliary machine for restoring it to its normal condition.

5. In an elevator system, the combination with a main machine and an auxiliary machine, of a hoisting cable operatively connected at one end to the main machine and at the other end to the auxiliary machine, a car suspended from said cable intermediate the said machines, means for operating said auxiliary machine after said machine has become ineffective and means for restoring said auxiliary machine to its normal position.

6. In an elevator system, the combination with a main machine and an auxiliary ma chine, of a hoisting cable operatively connccted at one end to the main machine and atthe other end to the auxiliary machine, a car suspended from said cable intermediate the said machines, means for operating said auxiliary machine after said main machine has become ineffective and means for restoring said auxiliary machine to its normal position between successive operations thereof.

7. In an elevator system, the combination with a main machine and an auxiliary machine, of a hoisting cable operatively connected at one end to the main machine and at the other end to the auxiliary machine, a car suspended from said cable intermediate the said machines, controlling means for said machine and automatic controlling means for said auxiliary machine for insuring accurate stops at any floor level, and means for automatically restoring said auxiliary machine to its normal condition.

8. In an elevator system, the combination with a main machine and'an auxiliary machine, of a hoisting cable operatively connected at one end to the main machine and at the other end to the auxiliary machine, a car suspended from said cable intermediate the said machine, controlling means for said machine, and switching means, automatically controlled bythe car, for controlling for controllingsaid auxiliary machine when the car switch is i'nefiective, and means for restoring said auxiliary machine to its normal position when said car switch is in an operative position.

10. In an elevator system, the combination With a main machine and an auxiliary ma- 7 chine, of a hoisting cable 'operatively connected at one end to the main machine andat the other end'to the auxiliary machine, a car suspended from the cable intermediate the said'machines, a car switch for controlling said main machine, a reversing switch controlled in accordancewith the position of the car, for controlling the auxiliary machine,

and switching means actuated by said auxiliary machine for controlling said auxiliary T 'machine independently of 'the reversing switch.

' In testimony whereof,

ary, 1922. t 1

RAY P. HIGBEE. t

I have hereunto, subscribed my'name this 10th day of'Janu 

